High-capacity batteries made from wood pulp

Ever heard of a battery made of wood pulp? Here is one, developed by researchers from KTH Royal Institute of Technology, Sweden, and Stanford University, US.

Using nanocellulose broken down from tree fibres, the researchers produced an elastic, foam-like battery material that can withstand shock and stress.

"It is possible to make incredible materials from trees and cellulose," said researcher Max Hamedi from KTH.

One benefit of the new wood-based aerogel material is that it can be used for three-dimensional structures.

"We are no longer restricted to two dimensions. We can build in three dimensions, enabling us to fit more electronics in a smaller space," Hamedi said.

A 3D structure enables storage of significantly more power in less space than is possible with conventional batteries, he said.

"Three-dimensional, porous materials have been regarded as an obstacle to building electrodes. But we have proven that this is not a problem. In fact, this type of structure and material architecture allows flexibility and freedom in the design of batteries," Hamedi said.

The process for creating the material begins with breaking down tree fibres, making them roughly one million times thinner.

The nanocellulose is dissolved, frozen and then freeze-dried so that the moisture evaporates without passing through a liquid state.

Then the material goes through a process in which the molecules are stabilised so that the material does not collapse.

The finished aerogel can then be treated with electronic properties. In terms of surface area, Hamedi compares the material to a pair of human lungs, which if unfurled could be spread over a football field.

Hamedi said the aerogel batteries could be used in electric car bodies, as well as in clothing, providing the garment has a lining.